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Patehted May I6, I899.

E. n. JOHNSTON. ROTARY BLOWER. (Application filed Apr. 29, 1898.)

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' Nrrnn STATES PATENT OFFICE.

EDGAR 1). JOHNSTON, OF CONNERSVILLE, INDIANA, ASSIGNOR o THE P. H. a F. M. ROOTS COMPANY, OF SAME PLACE.

ROTARY BLOWER.

SPECIFICATION forming partof Letters Patent No. 624,943, dated May 16, 1899. 4

Application filed April 29, 1898.

To all whom it may concern.-

'Be it known that I, EDGAR D. JOHNSTON, of Connersville, Fayette county, Indiana, have invented certain new and useful Improvements in Rotary Blowers, (Case (3,) of which the following is a specification.

This invention pertains to improvements in rotary blowers; and the improvements will be readily understood from the following description, taken in connection with the accom= panyingdrawings, in which Figure 1 is a vertical transverse section of a blower embodying my improvement, while Fig. 2 is a side elevation of the same, part appearing in vertical longitudinal section.

In the drawings, 1 indicates the case of a rotary blower of the well-known Roots type; 2, the fluid-inlet thereto, the same being disposed at the base of the casing and adapted to admit the fluid, be it air or gas, to the interior of the casing; 3, the fluid-outlet at the top of the casing; 4, the usual pair of intermembering impellers arranged on parallel axes between the fluid-inlet and the fluidoutlet of the casing, the interior walls of the casing being of a form to be swept by the ex tremities of the impellers; 5, a liquid-supply pipe leading to the casing from a source of supply of liquid, as water or oil, under pressure; 6, spray-heads arranged within the casing in connection with pipe 5, these sprayheads being located near the fluid-inlet 2 and between that' inlet and the impellers 4:, and being arranged to spray upwardly into the volume of fluid entering the fluid-inlet 2 and approaching the impellers, and 7 valves for controlling the flow of liquid to the sprayheads.

During the rotation of the impellers the' fluid being dealt with is drawn in at inlet 2 and gathered by the impellers and compressed and expelled at outlet 3. Spray-heads 6 inject finely-divided liquid upwardly into the fluid prior to its reaching the impellers, the liquid instantly becoming diffused with thefluid and going to the surfaces of the impellers and casing and being expelled from outlet 3 with the fluid, the entrained li quid passing onward with the compressed fluid or Serial Nb. 679,171. (No model.)

being trapped away therefrom by any usual or suitable trap, if desired. The liquid thus becoming entrained with the fluid before the fluid is attacked by the impellers bathes the contacting surfaces of the machine, lubricating those surfaces and packing the joints of contact and serving also in taking up some of the heat due to compression of the fluid. Valves 7 serve in regulating the amount of the liquid injected into the uncompressed fluid. Surplus liquid, not becoming fully entrained with the uncompressed fluid, may freely drain backward through fluid-inlet 2.

The amount of liquid received by the im-- pellers is thus only so much as becomes diffused with the fluid, any excess of liquid returning by gravity without passing through the blower. The blower thus requires to deal with and deliver only the liquid entrainedwith the fluid, and the possibilities of liquid in mass in the blower or discharge are avoided.

I claim as my invention- 1. In a rotary blower,the combination,sub-

.stantially as set forth, of a casing having a pressed fluid on its .way to the impellers,

wherebythe fluid-inlet serves also as the outlet for the rejected liquid.

2. In a fluid-compressor, the combination substantially as set forth, of a case provided with a fluid-inlet and a fluid-outlet, rotary impellers above the level of said inlet, a liqaid-spraying device disposed below the impellers and above the level of the inlet said fluid-inlet being arranged to receive the surplus liquid as it gravitates to the bottom of the case.

EDGAR D. JOHNSTON. Witnesses:

L. E. BLINN,

R. B. INsLEY. 

